From X-Rays to Quarks Quotes

“As Sommerfeld said in his famous text "Spectral Lines and Atomic Constitution," on which a generation of physicists learned the subject, "In the fine structure constant e is the representative of the electron theory, h the appropriate representative of the quantum theory, c comes from relativity and characterizes it in contrast to classical theory.”
― Emilio Segrè, From X-Rays to Quarks: Modern Physicists and Their Discoveries